diff --git a/server/services/collectors/cgroups.js b/server/services/collectors/cgroups.js
index eeec5d5..35cfb3d 100644
--- a/server/services/collectors/cgroups.js
+++ b/server/services/collectors/cgroups.js
@@ -199,6 +199,9 @@ export class CgroupsCollector extends EventEmitter {
     /** @type {Map<string, string>} */
     this._names = new Map()
     this._nameRefreshAt = 0
+    /** @type {Array<{ id: string, title: string, path: string }>|null} */
+    this._cgCache = null
+    this._cgTs = 0
   }
 
   start() {
@@ -253,18 +256,28 @@ export class CgroupsCollector extends EventEmitter {
     /** @type {Array<{ chart: string, context: string, ts: number, values: object }>} */
     const batch = []
 
-    for (const cg of discoverCgroups()) {
+    const now = Date.now()
+    if (!this._cgCache || now - this._cgTs > 30000) {
+      this._cgCache = discoverCgroups()
+      this._cgTs = now
+      for (const cg of this._cgCache) {
+        const title = resolveContainerLabel(cg.title, this._names)
+        registerChart(makeCgroupCpuChart(cg.id, title))
+        registerChart(makeCgroupMemChart(cg.id, title))
+        registerChart(makeCgroupIoChart(cg.id, title))
+        registerChart(makeCgroupMemDetailChart(cg.id, title))
+        registerChart(makeCgroupThrottleChart(cg.id, title))
+      }
+    }
+    const cgList = this._cgCache
+
+    for (const cg of cgList) {
       const title = resolveContainerLabel(cg.title, this._names)
       const cpuDef = makeCgroupCpuChart(cg.id, title)
       const memDef = makeCgroupMemChart(cg.id, title)
       const ioDef = makeCgroupIoChart(cg.id, title)
       const memDetailDef = makeCgroupMemDetailChart(cg.id, title)
       const throttleDef = makeCgroupThrottleChart(cg.id, title)
-      registerChart(cpuDef)
-      registerChart(memDef)
-      registerChart(ioDef)
-      registerChart(memDetailDef)
-      registerChart(throttleDef)
 
       const cpu = parseCpuStat(cg.path)
       let usageUsec = cpu?.usage_usec ?? 0
diff --git a/server/services/collectors/processes.js b/server/services/collectors/processes.js
index 4e3a969..d924804 100644
--- a/server/services/collectors/processes.js
+++ b/server/services/collectors/processes.js
@@ -212,7 +212,7 @@ function registerTopChart(names, kind) {
 export class ProcessCollector extends EventEmitter {
   constructor(opts = {}) {
     super()
-    this.intervalMs = opts.intervalMs || Number(process.env.PEARDATA_PROCESSES_MS) || Number(process.env.PEARDATA_SAMPLE_MS) || SAMPLE_INTERVAL_MS
+    this.intervalMs = opts.intervalMs || Number(process.env.PEARDATA_PROCESSES_MS) || Number(process.env.PEARDATA_SAMPLE_MS) || 3000
     this._timer = null
     /** @type {Map<number, { ticks: number, wallMs: number, name: string, readBytes: number, writeBytes: number }>|null} */
     this._prev = null
diff --git a/server/services/collectors/sensors.js b/server/services/collectors/sensors.js
index eead684..1f6589f 100644
--- a/server/services/collectors/sensors.js
+++ b/server/services/collectors/sensors.js
@@ -78,16 +78,66 @@ function makeSensorPowerChart(chip, label) {
   }
 }
 
+/**
+ * @returns {Array<{ chartId: string, context: string, values: Record<string, number> }>}
+ */
 /**
  * @returns {Array<{ chartId: string, context: string, values: Record<string, number> }>}
  */
 export function sampleSensors() {
   /** @type {Array<{ chartId: string, context: string, values: Record<string, number> }>} */
   const out = []
+
+  for (const entry of getSensorPaths()) {
+    let raw
+    if (entry._type === 'temp') {
+      raw = readFile(entry._inputPath)
+      if (raw == null) continue
+      const milli = Number(raw.trim())
+      if (!Number.isFinite(milli)) continue
+      out.push({ chartId: entry.chartId, context: entry.context, values: { temperature: milli / 1000 } })
+    } else if (entry._type === 'fan') {
+      raw = readFile(entry._inputPath)
+      if (raw == null) continue
+      const rpm = Number(raw.trim())
+      if (!Number.isFinite(rpm)) continue
+      out.push({ chartId: entry.chartId, context: entry.context, values: { rpm } })
+    } else if (entry._type === 'volt') {
+      raw = readFile(entry._inputPath)
+      if (raw == null) continue
+      const mv = Number(raw.trim())
+      if (!Number.isFinite(mv)) continue
+      out.push({ chartId: entry.chartId, context: entry.context, values: { millivolts: mv } })
+    } else if (entry._type === 'power') {
+      raw = readFile(entry._inputPath)
+      if (raw == null) continue
+      const uw = Number(raw.trim())
+      if (!Number.isFinite(uw)) continue
+      out.push({ chartId: entry.chartId, context: entry.context, values: { microwatts: uw } })
+    } else if (entry._type === 'thermal') {
+      raw = readFile(entry._inputPath)
+      if (raw == null) continue
+      const milli = Number(raw.trim())
+      if (!Number.isFinite(milli) || milli === 0) continue
+      const celsius = milli > 1000 ? milli / 1000 : milli
+      out.push({ chartId: entry.chartId, context: entry.context, values: { temperature: celsius } })
+    }
+  }
+  return out
+}
+
+let _sensorPaths = null
+let _sensorPathsTs = 0
+
+function getSensorPaths() {
+  const now = Date.now()
+  if (_sensorPaths && now - _sensorPathsTs < 30000) return _sensorPaths
+  _sensorPaths = []
+  _sensorPathsTs = now
+
   const hwmonRoot = '/sys/class/hwmon'
   try {
-    const chips = fs.readdirSync(hwmonRoot)
-    for (const chip of chips) {
+    for (const chip of fs.readdirSync(hwmonRoot)) {
       const dir = path.join(hwmonRoot, chip)
       const name = (readFile(path.join(dir, 'name')) || chip).trim()
       let ents
@@ -98,60 +148,40 @@ export function sampleSensors() {
       }
       for (const ent of ents) {
         const m = ent.match(/^temp(\d+)_input$/)
-        if (!m) continue
-        const n = m[1]
-        const raw = readFile(path.join(dir, ent))
-        if (raw == null) continue
-        const milli = Number(raw.trim())
-        if (!Number.isFinite(milli)) continue
-        const label =
-          (readFile(path.join(dir, `temp${n}_label`)) || `temp${n}`).trim() || `temp${n}`
-        const def = makeSensorTempChart(name, label)
-        registerChart(def)
-        out.push({
-          chartId: def.id,
-          context: def.context,
-          values: { temperature: milli / 1000 },
-        })
-      }
-      const fan = ent.match(/^fan(\d+)_input$/)
-      if (fan) {
-        const n = fan[1]
-        const raw = readFile(path.join(dir, ent))
-        if (raw == null) continue
-        const rpm = Number(raw.trim())
-        if (!Number.isFinite(rpm)) continue
-        const label =
-          (readFile(path.join(dir, `fan${n}_label`)) || `fan${n}`).trim() || `fan${n}`
-        const def = makeSensorFanChart(name, label)
-        registerChart(def)
-        out.push({ chartId: def.id, context: def.context, values: { rpm } })
-      }
-      const vin = ent.match(/^in(\d+)_input$/)
-      if (vin) {
-        const n = vin[1]
-        const raw = readFile(path.join(dir, ent))
-        if (raw == null) continue
-        const mv = Number(raw.trim())
-        if (!Number.isFinite(mv)) continue
-        const label =
-          (readFile(path.join(dir, `in${n}_label`)) || `in${n}`).trim() || `in${n}`
-        const def = makeSensorVoltageChart(name, label)
-        registerChart(def)
-        out.push({ chartId: def.id, context: def.context, values: { millivolts: mv } })
-      }
-      const pwr = ent.match(/^power(\d+)_input$/)
-      if (pwr) {
-        const n = pwr[1]
-        const raw = readFile(path.join(dir, ent))
-        if (raw == null) continue
-        const uw = Number(raw.trim())
-        if (!Number.isFinite(uw)) continue
-        const label =
-          (readFile(path.join(dir, `power${n}_label`)) || `power${n}`).trim() || `power${n}`
-        const def = makeSensorPowerChart(name, label)
-        registerChart(def)
-        out.push({ chartId: def.id, context: def.context, values: { microwatts: uw } })
+        if (m) {
+          const n = m[1]
+          const label = (readFile(path.join(dir, `temp${n}_label`)) || `temp${n}`).trim() || `temp${n}`
+          const def = makeSensorTempChart(name, label)
+          registerChart(def)
+          _sensorPaths.push({ chartId: def.id, context: def.context, _type: 'temp', _inputPath: path.join(dir, ent) })
+          continue
+        }
+        const fan = ent.match(/^fan(\d+)_input$/)
+        if (fan) {
+          const n = fan[1]
+          const label = (readFile(path.join(dir, `fan${n}_label`)) || `fan${n}`).trim() || `fan${n}`
+          const def = makeSensorFanChart(name, label)
+          registerChart(def)
+          _sensorPaths.push({ chartId: def.id, context: def.context, _type: 'fan', _inputPath: path.join(dir, ent) })
+          continue
+        }
+        const vin = ent.match(/^in(\d+)_input$/)
+        if (vin) {
+          const n = vin[1]
+          const label = (readFile(path.join(dir, `in${n}_label`)) || `in${n}`).trim() || `in${n}`
+          const def = makeSensorVoltageChart(name, label)
+          registerChart(def)
+          _sensorPaths.push({ chartId: def.id, context: def.context, _type: 'volt', _inputPath: path.join(dir, ent) })
+          continue
+        }
+        const pwr = ent.match(/^power(\d+)_input$/)
+        if (pwr) {
+          const n = pwr[1]
+          const label = (readFile(path.join(dir, `power${n}_label`)) || `power${n}`).trim() || `power${n}`
+          const def = makeSensorPowerChart(name, label)
+          registerChart(def)
+          _sensorPaths.push({ chartId: def.id, context: def.context, _type: 'power', _inputPath: path.join(dir, ent) })
+        }
       }
     }
   } catch {
@@ -164,20 +194,15 @@ export function sampleSensors() {
       if (!zone.startsWith('thermal_zone')) continue
       const dir = path.join(thermalRoot, zone)
       const type = (readFile(path.join(dir, 'type')) || zone).trim()
-      const raw = readFile(path.join(dir, 'temp'))
-      if (raw == null) continue
-      const milli = Number(raw.trim())
-      if (!Number.isFinite(milli) || milli === 0) continue
-      // some platforms report already in C
-      const celsius = milli > 1000 ? milli / 1000 : milli
       const def = makeThermalZoneChart(zone, type)
       registerChart(def)
-      out.push({ chartId: def.id, context: def.context, values: { temperature: celsius } })
+      _sensorPaths.push({ chartId: def.id, context: def.context, _type: 'thermal', _inputPath: path.join(dir, 'temp') })
     }
   } catch {
     // no thermal
   }
-  return out
+
+  return _sensorPaths
 }
 
 export class SensorsCollector extends EventEmitter {